Genetic basis for the evolution of vertebrate mineralized tissue

Mineralized tissue is vital to many characteristic adaptive phenotypes in vertebrates. Three primary tissues, enamel (enameloid), dentin, and bone, are found in the body armor of ancient agnathans and mammalian teeth, suggesting that these two organs are homologous. Mammalian enamel forms on enamel-specific proteins such as amelogenin, whereas dentin and bone form on collagen and many acidic proteins, such as SPP1, coordinately regulate their mineralization. We previously reported that genes for three major enamel matrix proteins, five proteins necessary for dentin and bone formation, and milk caseins and salivary proteins arose from a single ancestor by tandem gene duplications and form the secretory calcium-binding phosphoprotein (SCPP) family. Gene structure and protein characteristics show that SCPP genes arose from the 5' region of ancestral sparcl1 (SPARC-like 1). Phylogenetic analysis on SPARC and SPARCL1 suggests that the SCPP genes arose after the divergence of cartilaginous fish and bony fish, implying that early vertebrate mineralization did not use SCPPs and that SPARC may be critical for initial mineralization. Consistent with this inference, we identified SPP1 in a teleost genome but failed to find any genes orthologous to mammalian enamel proteins. Based on these observations, we suggest a scenario for the evolution of vertebrate tissue mineralization, in which body armor initially formed on dermal collagen, which acted as a reinforcement of dermis. We also suggest that mammalian enamel is distinct from fish enameloid. Their similar nature as a hard structural overlay on exoskeleton and teeth is because of convergent evolution.     

Improved survival of idiopathic dilated cardiomyopathy in the 1990s

To analyze the recent change in the long-term survival of patients with dilated cardiomyopathy (DCM), the present study comprised consecutive 111 patients with ejection fraction <50% and left ventricular end-diastolic diameter >58 mm. who were admitted to hospital from January 1983 to December 1994. The patients were divided into 2 groups: group A who were diagnosed before 1989 and group B diagnosed after 1990. Basic characteristics at diagnosis, including age, NYHA functional class, left ventricular end-diastolic diameter and ejection fraction, were similar between these 2 groups. Calculated survival rate at 5 years was 90.0% in group B in contrast to 62.3% in group A. Event-free survival also improved in group B. In group B, beta-blockers and angiotensin converting enzyme inhibitors were more frequently used than in group A (p<0.0001) whereas digitalis and other positive inotropic agents were significantly less used. Left ventricular ejection fraction was significantly improved during the follow-up period in patients treated with beta-blockers compared with those not treated with beta-blockers. These data indicate a significant improvement in the survival of patients with dilated cardiomyopathy after 1990, which may be explained by the change of medical treatment, especially the use of beta-blockers.     

Vascularity of advanced gastric carcinoma: evaluation by using power Doppler imaging

BACKGROUND: We investigated the vascularity of advanced gastric adenocarcinomas by using percutaneous power Doppler imaging. METHODS: Seventeen patients with gastric cancer and 10 without a gastric tumor, but with a slightly thick gastric wall in the B-mode ultrasound, were investigated with the use of power Doppler imaging. The color signals of the gastric lesion were graded as follows: 1, no color signals or the same as the surroundings; 2, color signals were slightly increasing; and 3, color signals were obviously increasing. RESULTS: The color signals of three patients were graded 1, those of eight patients were graded 2 and those of six patients were graded 3 in the gastric cancer group. The color signals of all 10 patients without a gastric tumor were grade 1. This difference was statistically significant (P = 0.0002). CONCLUSIONS: Power Doppler imaging showed vascularity of gastric cancer increasing in the majority of patients (14 of 17: 82%). Thus, power Doppler imaging might be a good screening examination method for gastric cancer.     

Autologous chondrocytes transplantation

Hunter's observation in 1743 that cartilage "once destroyed, is not repaired" has not essentially changed for two and a half centuries. At present, there is no well-established procedure for the repair of cartilage defect with articular cartilage. Transplantation of human autologous chondrocytes in suspension, as reported by Brittberg et al., provided a potential procedure for articular cartilage repair. We have improved their procedure and developed a new technique, which creates new cartilage-like tissue by cultivating autologous chondrocytes embedded in atelocollagen gel for 3 weeks before transplantation. Good clinical results suggest that this technique should be a promising procedure for repairing articular cartilage defect.